1. Field of the Invention
The present invention relates to a print element substrate, printhead, and printing apparatus.
2. Description of the Related Art
There is known a printing apparatus which employs an inkjet printing system. The printing apparatus of this system generally includes a printhead in which a plurality of printing elements are arrayed. The printing apparatus prints an image by scanning the printhead with respect to a printing medium.
Japanese Patent Laid-Open No. 2001-080060 discloses a method of inputting serial data for driving a printing element in a printhead, and serially outputting digital information such as temperature data and head characteristic information.
In this method, the printhead includes an input shift register for inputting serial data for driving a printing element, and an output shift register for digitalizing temperature data in the printhead and serially outputting it.
However, in Japanese Patent Laid-Open No. 2001-080060, two shift registers, that is, an input shift register and output shift register need to be arranged on the same substrate, increasing the circuit scale and substrate size.
In the semiconductor manufacturing process, the substrate size needs to be decreased to increase the number of substrates obtained from a single wafer and reduce the cost. Hence, the increase in substrate size raises the cost.
Recently, printheads (substrates) are increasing the number of printing elements and becoming long for higher resolutions and higher speeds. Achieving high-quality printing requires driving control of printing elements in accordance with the temperature distribution within the substrate. Accordingly, temperature detection at a plurality of portions within the substrate becomes necessary.
When a plurality of temperature detection circuits are arranged in the substrate, wiring lines for outputting detection information also become long along with the elongation of the substrate, increasing the wiring area inside the substrate. This also leads to a large substrate size.
The present invention has been made to solve the above problems, and has as its object to provide a technique for suppressing the circuit scale of a print element substrate for outputting substrate information, and implementing shrinkage of the substrate size.